How to seperate extruded part from its attach boundary in image processing ?

I want to seperate the extrude part

Answer 1

[Image Analyst]

Try bwskel to identify the longest spine, then dilate it and use it as a mask on the original.

[Image Analyst]

You thresholded wrong. You need to invert it so that the cark blob is the foreground (white).

[Image Analyst]

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